For example, an existing multi-air-conditioning apparatus for a building circulates refrigerant between an outdoor unit which is a heat source unit installed outside a building and indoor units installed within rooms of the building. Then, the refrigerant rejects and receives heat to heat and cool air with which an air-conditioning target space is cooled or heated. As refrigerant, for example, HFC (hydrofluorocarbon) refrigerant is used in many cases, and a multi-air-conditioning apparatus which uses natural refrigerant such as CO2 has also been proposed.
In addition, there is a so-called total heat recovery type air-conditioning apparatus in which a flow division controller which controls and distributes flow of the refrigerant is connected between an outdoor unit and indoor units, and which exchanges heat to be released to the outside of a building via the outdoor unit, between the indoor units, and causes each indoor unit to independently perform cooling or heating in a single air-conditioning system (e.g., see Patent Literature 1).
Moreover, in an air-conditioning apparatus called a chiller, a heat source unit installed outside a building generates cooling energy or heating energy. A heat exchanger disposed within the heat source unit heats or cools water, an antifreezing solution, or the like (hereinafter, representatively referred to as water), and sends out the water to a fan coil unit, a panel heater, or the like installed within a room, to perform cooling or heating.
There is also an air-conditioning apparatus called a waste heat recovery type chiller in which four water pipes are connected between a heat source unit and an indoor unit, cooled or heated water is supplied simultaneously therethrough, and cooling or heating is freely selectable at the indoor unit.
In the air-conditioning apparatus described in Patent Literature 1, since the refrigerant is circulated to the indoor units, there is a possibility that the refrigerant leaks within the room. Meanwhile, in an air-conditioning apparatus such as a chiller or a waste heat recovery type chiller, refrigerant does not pass through the indoor unit, but it is necessary to send water from outside of the building to the indoor unit side. Thus, a water circulation path becomes long, and energy consumption such as water sending power is higher than that of the refrigerant, so that the efficiency is poor. In addition, in an air-conditioning apparatus such as a waste heat recovery type chiller, in order to allow cooling or heating to individually be selected for each indoor unit, the outdoor unit and each indoor unit have to be connected to each other via four pipes in total, and thus the installability further deteriorates.
From the above, it is thought that it is possible to solve the above-described problem if a method is established in which heat obtained by a total heat recovery type air-conditioning apparatus such as the air-conditioning apparatus described in Patent Literature 1 is given to water, and the water is supplied to each indoor unit.
Furthermore, the above-described method requires a device which exchanges heat between refrigerant and water, and a device which sends water to each indoor unit. In addition, in the case where these devices are individually installed, installation spaces, maintenance spaces, and an operation of connecting pipes which connect these devices to each other, an operation for heat insulation, and the like are required, so that the installability deteriorates. Thus, these devices are desired to be integrated with each other (e.g., see Patent Literature 2). In addition, these devices are installed above a ceiling in many cases.